The invention provides keyboard systems that auto-correct xe2x80x9csloppyxe2x80x9d text entry due to errors in touching a keyboard or screen. More specifically, the invention provides a reduced keyboard such as those implemented on a touch-sensitive panel or display screen and to mechanical keyboard systems, using word-level analysis to resolve inaccuracies (sloppy text entry) in user entries. This invention is in the field of keypad input preferably for small electronic devices.
For many years, portable computers have been getting smaller and smaller. The principal size-limiting component in the effort to produce a smaller portable computer has been the keyboard. If standard typewriter-size keys are used, the portable computer must be at least as large as the keyboard. Miniature keyboards have been used on portable computers, but the miniature keyboard keys have been found to be too small to be easily or quickly manipulated with sufficient accuracy by a user.
Incorporating a full-size keyboard in a portable computer also hinders true portable use of the computer. Most portable computers cannot be operated without placing the computer on a flat work surface to allow the user to type with both hands. A user cannot easily use a portable computer while standing or moving. In the latest generation of small portable computers, called Personal Digital Assistants (PDAs), companies have attempted to address this problem by incorporating handwriting recognition software in the PDA. A user may directly enter text by writing on a touch-sensitive panel or display screen. This handwritten text is then converted into digital data by the recognition software. Unfortunately, in addition to the fact that printing or writing with a pen is in general slower than typing, the accuracy and speed of the handwriting recognition software has to date been less than satisfactory. To make matters worse, today""s handheld computing devices which require text input are becoming smaller still. Recent advances in two-way paging, cellular telephones, and other portable wireless technologies has led to a demand for small and portable two-way messaging systems, and especially for systems which can both send and receive electronic mail (xe2x80x9ce-mailxe2x80x9d).
It would therefore be advantageous to develop a much smaller keyboard for entry of text into a computer. As the size of the keyboard is reduced, the user encounters greater difficulty selecting the character of interest. In general there are two different types of keyboards utilized in such portable devices. One is the familiar mechanical keyboard consisting of a set of mechanical keys that are activated by depressing them with a finger or thumb. However, these mechanical keyboards tend to be significantly smaller than the standard sized keyboards associated with typewriters, desktop computers, and even xe2x80x9claptopxe2x80x9d computers. As a result of the smaller physical size of the keyboard, each key is smaller and in closer proximity to neighboring keys. This increases the likelihood that the user will depress an unintended key, and the likelihood of keystroke errors tends to increase the faster the user attempts to type.
Another commonly used type of keyboard consists of a touch-sensitive panel on which some type of keyboard overlay has been printed, or a touch-sensitive display screen on which a keyboard overlay can be displayed. Depending on the size and nature of the specific keyboard, either a finger or a stylus can be used to contact the panel or display screen within the area associated with the key that the user intends to activate. Due to the reduced size of many portable devices, a stylus is often used in order to attain sufficient accuracy in contacting the keyboard to activate each intended key. Here again, the small overall size of such keyboards results in a small area being associated with each key so that it becomes quite difficult for the average user to type quickly with sufficient accuracy.
One area of prior development in mechanical keyboards has considered the use of keys that are much smaller than those found on common keyboards. With smaller keys, the user must take great care in controlling each key press. One approach (U.S. Pat. No. 5,612,690) proposes a system that uses up to four miniature keys in unison to define primary characters (the alphabet) and nests secondary character rows (like numbers) between primary character rows. Selecting a secondary character involves depressing the miniature key from each of the surrounding primary characters. Grouping the smaller keys in this fashion creates a larger apparent virtual key composed of four adjacent smaller keys, such that the virtual key is large enough to be depressed using a finger. However, the finger must contact the keys more or less precisely on the xe2x80x9ccross-hairsxe2x80x9d of the boundaries between the four adjacent keys in order to depress them in unison. This makes it still difficult to type quickly with sufficient accuracy.
Another area of prior development in both touch screen and mechanical keyboards has considered the use of a much smaller quantity of full-size keys. With fewer keys, each single key press must be associated with a plurality of letters, such that each key activation is ambiguous as to which letter is intended. As suggested by the keypad layout of a touch-tone telephone, many of the reduced keyboards have used a 3-by-4 array of keys, where each key is associated with three or four characters (U.S. Pat. No. 5,818,437). Several approaches have been suggested for resolving the ambiguity of a keystroke sequence on such a keyboard. While this approach has merit for such keyboards with a limited number of keys, it is not applicable to reduced size keyboards with a full complement of keys.
Another approach in touch screen keyboards has considered analyzing the immediately preceding few characters in order to determine which character should be generated for a keystroke that is not close to the center of the display location of a particular character (U.S. Pat. No. 5,748,512). When the keyboard is displayed on a small touch screen, keystrokes that are off-center from a character are detected. Software compares the possible text strings of probable sequences of two or three typed characters against known combinations, such as a history of previously typed text or a lexicon of text strings rated for their frequency within a context. When the character generated by the system is not the character intended by the user, the user must correct the character before going on to select the a following character, because the generated character will be used to determine probabilities for the following keystroke.
The fundamental problem is that the specific activations that result from a user""s attempts to activate the keys of a keyboard do not always precisely conform to the intentions of the user. On a touch screen keyboard, the user""s finger or stylus may hit the wrong character or hit between keys in a boundary area not associated with a specific character. With a miniaturized mechanical keyboard, a given keypress may activate the wrong key, or may activate two or more keys either simultaneously or with a xe2x80x9croll-overxe2x80x9d motion that activates adjacent keys in a rapid sequence. Other examples include common keyboards operated by users with limited ranges of motion or motor control, where there is a limited ability to consistently strike any particular space or key, or where the limb (such as in the case of an amputee, or the use of gloved hands or gloved fingers) or the device used to make the entry (such as a stylus) is far larger than the targeted key or character space.
The present invention provides an enhanced text entry system that uses word-level disambiguation to automatically correct inaccuracies in user keystroke entries. Specifically, the present invention provides a text entry system comprising:
(a) a user input device comprising a touch sensitive surface including an auto-correcting keyboard region comprising a plurality of the characters of an alphabet, wherein each of the plurality of characters corresponds to a location with known coordinates in the auto-correcting keyboard region, wherein each time a user contacts the user input device within the auto-correcting keyboard region, a location associated with the user contact is determined and the determined contact location is added to a current input sequence of contact locations;
(b) a memory containing a plurality of objects, wherein each object is a string of one or a plurality of characters forming a word or a part of a word, wherein each object is further associated with a frequency of use;
(c) an output device with a text display area; and
(d) a processor coupled to the user input device, memory, and output device, said processor comprising:
(i) a distance value calculation component which, for each determined contact location in the input sequence of contacts, calculates a set of distance values between the contact locations and the known coordinate locations corresponding to one or a plurality of characters within the auto-correcting keyboard region;
(ii) a word evaluation component which, for each generated input sequence, identifies one or a plurality of candidate objects in memory, and for each of the one or a plurality of identified candidate objects, evaluates each identified candidate object by calculating a matching metric based on the calculated distance values and the frequency of use associated with the object, and ranks the evaluated candidate objects based on the calculated matching metric values; and
(iii) a selection component for (a) identifying one or a plurality of candidate objects according to their evaluated ranking, (b) presenting the identified objects to the user, enabling the user to select one of the presented objects for output to the text display area on the output device.
Preferably, the selection component further comprises (c) resetting the current input sequence of contact locations to an empty sequence upon detecting the selection by the user of one of the presented objects for output to the text display area on the output device.
Preferably, (a) each of the plurality of objects in memory is further associated with one or a plurality of predefined groupings of objects; and (b) the word evaluation component, for each generated input sequence, limits the number of objects for which a matching metric is calculated by identifying one or a plurality of candidate groupings of the objects in memory, and for one or a plurality of objects associated with each of the one or a plurality of identified candidate groupings of objects, calculates a matching metric based on the calculated distance values and the frequency of use associated with each candidate object, and ranks the evaluated candidate objects based on the calculated matching metric values. This reduces the calculation required since, conversely, one or more groupings of objects are identified as containing no candidate objects for a given input sequence of contacts, such that a matching metric need not be calculated for any object in the groupings so identified.
Preferably, the characters of the alphabet are arranged on the auto-correcting keyboard region in approximately a standard xe2x80x9cQWERTYxe2x80x9d layout. Most preferably, the width to height ratio of the auto-correcting keyboard region is approximately 2 to 1, or the width to height ratio of the auto-correcting keyboard region is less than 2 to 1. In one embodiment, one or a plurality of the characters arranged on the auto-correcting keyboard region are illegible.
Preferably, the auto-correcting keyboard region includes one or a plurality of known locations associated with one or a plurality of punctuation characters, wherein the memory includes one or a plurality of objects in memory which include one or a plurality of the punctuation characters associated with locations in the auto-correcting keyboard region. Preferably, the objects in memory are further associated with one or a plurality of modules, wherein each module comprises a set of objects with one or a plurality of common characteristics. In one embodiment, the text entry system comprises a module selector whereby a user can determine which modules are to be evaluated by the word evaluation component in order to identify candidate objects. In another embodiment, the plurality of modules comprises word stem modules and suffix modules, wherein each word stem module comprises a logical organization of uninflected word stem objects, and wherein each suffix module comprises a logical organization of suffixes which can be appended to word stems to form inflected words, whereby each word stem module is associated with one or a plurality of suffix modules, whereby whenever the word evaluation component calculates a matching metric value for a given word stem in a given word stem module with respect to an initial sequence of contacts within an input sequence such that the calculated matching metric value ranks higher than a predetermined threshold, the word evaluation component evaluates the remaining contacts of the input sequence with respect to the associated suffix modules, whereby whenever the word evaluation component calculates a matching metric value for a given suffix in one of said associated suffix modules that ranks higher than a second predetermined threshold, said suffix is appended to said word stem to form a completed word corresponding to a matching metric value that is a function of said determined word stem matching metric value and said determined suffix matching metric value.
Preferably, the word evaluation component calculates the matching metric for each candidate object by summing the distance values calculated from each contact location in the input sequence to the location assigned to the character in the corresponding position of the candidate object, and applying a weighting function according to the frequency of use associated with the object. In addition, each character of the alphabet associated with the auto-correcting keyboard region is assigned a Cartesian coordinate and wherein the distance value calculation component calculates the distance between the contact location and the location corresponding to a character according to standard Cartesian coordinate distance analysis. Further, each character of the alphabet associated with the auto-correcting keyboard region is assigned a Cartesian coordinate and wherein the distance value calculation component calculates the distance between the contact location and the location corresponding to a character as the square of the standard Cartesian coordinate distance. The distance values are placed in a table. In addition, each location on the auto-correcting keyboard region is defined by a horizontal and a vertical coordinate, and wherein the distance value between a contact location and the known coordinate location corresponding to a character comprises a horizontal and a vertical component, wherein the vertical component is adjusted by a weighting factor in calculating the distance of the contact location from the character. The word evaluation component adds an increment value to the sum of the distance values prior to applying a weighting function according to the frequency of use associated with the candidate object. Most preferably, the increment value is a fixed value that is approximately twice the average distance between adjacent locations on the auto-correcting keyboard region corresponding to characters. The frequency of use associated with each candidate object in memory comprises the ordinal ranking of the object with respect to other objects in memory, wherein an object associated with a higher relative frequency corresponds to a numerically lower ordinal ranking. Most preferably, the frequency weighting function applied by the word evaluation component to the summed distance values for a candidate object comprises multiplying the sum of the distance values by the base 2 logarithm of the ordinal ranking of the object.
Preferably, objects in memory are stored such that the objects are classified into groupings comprising objects of the same length. The word evaluation component limits the number of objects for which a matching metric is calculated by initially identifying candidate groupings of objects of the same length as the number of inputs in the input sequence. Most preferably, if fewer than a threshold number of candidate objects are evaluated to have a matching metric score better than a threshold value, the word evaluation component identifies candidate groupings of objects of progressively longer lengths and calculates the matching metric for the objects in the identified groupings until said threshold number of candidate objects are evaluated to have a matching metric score better than said threshold. Further, the word evaluation component calculates the matching metric for each candidate object by summing the distance values calculated from each contact location in the input sequence to the location assigned to the character in the corresponding position of the candidate object and adding an increment value, and applying to this sum a weighting function according to the frequency of use associated with the object, and wherein the increment value added to the sum of the distance values is a value that is based on the difference between the number of characters in the candidate object and the number of inputs in the current input sequence.
Preferably, the word evaluation component calculates the matching metric for each candidate object by summing the distance values calculated from each contact location in the input sequence to the location assigned to the character in the corresponding position of the candidate object, and applying a weighting function according to the frequency of use associated with the object. Most preferably, the frequency of use associated with each candidate object in memory comprises the ordinal ranking of the object with respect to other objects in one or a plurality of sub-groupings in memory with which said object is associated, wherein an object associated with a higher relative frequency corresponds to a numerically lower ordinal ranking. In addition, for each calculated distance value between a contact location in the input sequence and the known coordinate location corresponding to a character within the auto-correcting keyboard region wherein said calculated distance exceeds a threshold distance value, for each object in memory in which said character occurs at a position in the sequence of the characters of said object corresponding to the position of said contact location in said input sequence, said object is ranked by the word evaluation component as an object that is excluded from presentation to the user for selection. One or a plurality of the identified candidate groupings of the objects in memory comprise objects that are excluded from presentation to the user for selection, wherein at least one of the calculated distance values included in the calculated sum of distance values for each object in said one or identified candidate groupings of objects exceeds a threshold distance value. The auto-correcting keyboard region is separated into two or more predefined clustering regions, each of which contains the known locations of one or a plurality of characters, and wherein each objects in memory is assigned to a predefined group according to which of said two or more predefined clustering regions contain the known locations corresponding to one or a plurality of the initial characters of said object. In one embodiment, the auto-correcting keyboard region is separated into three predefined clustering regions, and wherein each object in memory is assigned to one of nine predefined groupings based which of the three predefined clustering regions contain the known locations corresponding to each of the first two characters of said object.
Preferably, for each character corresponding to a known location in the auto-correcting keyboard region, a region is predefined around one or a plurality of said known locations wherein the distance between an input contact location falling within said predefined region and the known character location within said predefined region is calculated as a distance of zero. Most preferably, the relative sizes of said predefined regions correspond to the relative frequencies of occurrence of the characters associated with the known locations within said predefined regions. The predefined region around the known location of a character corresponds to a displayed key on the touch screen. Further, at least one of the locations with known coordinates in the auto-correcting keyboard region corresponds to a plurality of characters, one or a plurality of which include various diacritic marks, wherein the plurality of characters comprise variant forms of a single base character, and wherein objects in memory are stored with their correct accented characters.
Preferably, the selection component presents the identified one or a plurality of candidate objects for selection by the user in a candidate object list in the text display area. Most preferably, the selection component identifies the highest ranked candidate object and presents the identified object in the candidate object list in the position nearest to the auto-correcting keyboard region. In addition, user selection of a character that is associated with a contact outside of the auto-correcting keyboard region accepts and outputs the determined highest ranked candidate object at a text insertion point in the text display area prior to outputting the selected character at the text insertion point in the text display area. The user selection of an object for output at a text insertion point in the text display area terminates the current input sequence such that the next contact within the auto-correcting keyboard region starts a new input sequence. In addition, the selection component detects a distinctive manner of selection that is used to select a candidate object, and wherein upon detecting that an object has been selected through said distinctive manner, the system replaces the current input sequence of actual contact locations with an input sequence of contact locations corresponding to the coordinate locations of the characters comprising the selected object, and wherein a next contact in the auto-correcting keyboard region is appended to the current input sequence.
Preferably, the word evaluation component determines, for each determined contact location in each input sequence of contact locations, the closest known location corresponding to a character, and constructs an exact typing object composed of said determined corresponding characters in the order corresponding to the input sequence of contact locations. Most preferably, for each input sequence of contact locations, the selection component presents said exact typing object to the user for selection. Further, when the user selects said exact typing object for output to the text display area on the output device and said exact typing object is not already included as one of the objects in memory, said exact typing object is added to the memory. Prior to displaying the exact typing object to the user for selection, the selection component compares the exact typing object to a database of offensive objects, each of which is associated with an acceptable alternative object for display, and if a match is found, replaces the exact typing object with the associated acceptable object for presentation to the user.
Preferably, the selection component identifies the highest ranked candidate object and presents the identified object at the text insertion point in the text display area on the output device. Most preferably, the text entry system includes a select key region associated with an object selection function, wherein when said select key region is contacted, the object presented at the text insertion point in the text display area on the output device is replaced with next highest ranked object of the identified one or a plurality of candidate objects.
Preferably, the text entry system includes a delete key region associated with a delete function, wherein when the current input sequence includes at least one contact and said delete key region is contacted, the last input contact from the current input sequence of contacts is deleted, without terminating the current input sequence. In another preferred embodiment, the text entry system includes an Edit Word key region associated with an Edit Word function, wherein when no current input sequence exists and said Edit Word key region is contacted:
(i) when the text insertion point in the text display area on the output device is contained within a previously output word, the system establishes a new current input sequence consisting of a sequence of contact locations corresponding to the coordinate locations associated with the characters of said word, and
(ii) when the text insertion point in the text display area on the output device is located between two previously output words, the system establishes a new current input sequence consisting of a sequence of contact locations corresponding to the coordinate locations associated with the characters of the word adjacent to the text insertion point, and wherein the text entry system processes said new current input sequence and determines a corresponding ranking of new candidate objects, and wherein selection of one of the new candidate objects replaces the previously output word used to establish said new current input sequence.
Preferably, as the user enters an input sequence by performing a sequence of contact actions within the auto-correcting keyboard region, the processor determines the location associated with each user contact action by recording each contact action in the sequence as an indexed primary set of a fixed number of two or more regularly spaced contact points along the path traced out by the user contact action, and by assembling two or more corresponding secondary sets of contact points by taking, for each of the two or more possible primary index values, the sequence of contact points having the same index value, one from each recorded indexed primary set of contact points, and by determining with respect to each word is selected by the user for output, a minimizing primary index value that identifies the assembled secondary set of contact points for which the calculated distance between the assembled secondary set of contact points and the known locations corresponding to the characters of the selected word is minimized, and whereby for a next input sequence of user contact actions, the distance value calculation component calculates distance values based on a sequence of contact locations determined as the secondary set of contact point locations assembled from said next input sequence of contact actions corresponding to the determined minimizing primary index value. Most preferably, for a plurality of user input sequences, the distance value calculation component computes a running average of the distance calculations for each of the two or more assembled secondary sets corresponding to the two or more primary index values, and whereby for a next input sequence of contact actions, the distance value calculation component calculates distance values based on a sequence of contact locations determined as the secondary set of contact point locations assembled from said next input sequence of contact actions corresponding to the minimizing primary index value determined with respect to said computed running averages. Further, for each primary index value, the distance value calculation component computes a running average of the horizontal and vertical components of the offset of the coordinate location corresponding to each character of each selected word with respect to the coordinate location of each corresponding recorded indexed contact point, and wherein in performing distance calculations for the word evaluation component, the distance value calculation component adjusts the horizontal and vertical coordinates of each recorded indexed contact point by an amount that is a function of the average horizontal and vertical offsets computed with respect to the corresponding primary index value.
Preferably, for each input contact location, the distance value calculation component computes a running average of the horizontal and vertical components of the offset of the coordinate location corresponding to each character of each selected word with respect to the coordinates of each corresponding input contact location, and wherein in performing distance calculations for the word evaluation component, the distance value calculation component adjusts the horizontal and vertical coordinates of each input contact location by amounts that are functions of the computed average signed horizontal and vertical offsets. Alternatively, the processor further comprises a stroke recognition component that determines for each user contact action within the auto-correcting keyboard region whether the point of contact is moved less than a threshold distance from the initial contact location prior to being lifted from the touch sensitive surface, whereby:
(a) when the point of contact is moved less than a threshold distance from the initial contact location prior to being lifted from the touch sensitive surface, the stroke recognition component determines that the user contact is a tap contact, and the location determined to be associated with the user contact is added to the current input sequence of contact locations to be processed by the distance value calculation component, the word evaluation component, and the selection component, and
b) when the point of contact is moved greater than or equal to a threshold distance from the initial contact location prior to being lifted from the touch sensitive surface, the stroke recognition component determines that the user contact is one of a plurality of stroke contacts that are associated with known system functions, and classifies the stroke contact as one of the plurality of predefined types of stroke contacts.
Preferably, when a threshold number of contact locations in the input sequence are further than a threshold maximum distance from the corresponding character in the sequence of characters comprising a given candidate object, said object is identified as no longer being a candidate object for the selection component. Alternatively, the processor further comprises a frequency promotion component for adjusting the frequency of use associated with each object in memory as a function of the number of times the object is selected by the user for output to the text display area on the output device. Moreover, the frequency of use associated with each object in memory comprises the ordinal ranking of the object with respect to other objects in memory, wherein an object associated with a higher relative frequency corresponds to a numerically lower ordinal ranking, and wherein when an object is selected for output by the user, the frequency promotion component adjusts the ordinal ranking associated with said selected object by an amount that is a function of the ordinal ranking of said object prior to said adjustment. Further, the function used by the frequency promotion component to determine the amount by which the ordinal ranking associated with a selected object is adjusted reduces said amount for objects with ordinal rankings that are associated with relatively higher frequencies of use. The frequency promotion component analyzes additional information files that are accessible to the text entry system to identify new objects contained in said files that are not included among the objects already in said memory of said text entry system, and wherein said newly identified objects are added to the objects in memory as objects that are associated with a low frequency of use. Further, the frequency of use associated with a newly identified object that is added to the objects in memory is adjusted by the frequency promotion component as a function of the number of times that the newly identified object is detected during the analysis of said additional information files.
Preferably, the processor further comprises a frequency promotion component for adjusting the frequency of use associated with each object in memory as a function of the number of times the object is selected by the user for output to the text display area on the output device with respect to other objects associated with the same predefined grouping. Most preferably, when an object is selected by the user for output to the text display area on the output device, the frequency promotion component increases the value of the frequency associated with the selected object by a relatively large increment, and decreases by a relatively small decrement the frequency associated with unselected objects that are associated with the same grouping as the selected object. Alternatively, information regarding the capitalization of one or a plurality of objects is stored along with the objects in memory and wherein the selection component presents each identified object in a preferred form of capitalization according to the stored capitalization information. In another embodiment, one or a plurality of objects in memory are associated with a secondary object in memory comprising a sequence of one or a plurality of letters or symbols, and wherein when the selection component identifies one of said objects for presentation to the user based on the matching metric calculated by the word evaluation component, the selection component presents the associated secondary object for selection.
The present invention further provides a text entry system comprising:
(a) a user input device comprising a keyboard constructed with mechanical keys including an auto-correcting keyboard region comprising a plurality of keys, each corresponding to a character of an alphabet and each at a known coordinate location, wherein each time a user activates one or a plurality of adjacent keys in the auto-correcting keyboard region within a predetermined threshold period of time to generate a key activation event, a determined location corresponding to the key activation event is appended to a current input sequence of the determined locations of the key activation events;
(b) a memory containing a plurality of objects, wherein each object is a string of one or a plurality of characters forming a word or a part of a word, wherein each object is further associated with a frequency of use;
(c) an output device with a text display area; and
(d) a processor coupled to the user input device, memory, and output device, said processor comprising:
(i) a distance value calculation component which, for each generated key activation event location in the input sequence of key activation events, calculates a set of distance values between the key activation event location and the known coordinate locations corresponding to one or a plurality of keys within the auto-correcting keyboard region;
(ii) a word evaluation component which, for each generated input sequence, identifies one or a plurality of candidate objects in memory, and for each of the one or a plurality of identified candidate objects, evaluates each identified candidate object by calculating a matching metric based on the calculated distance values and the frequency of use associated with the object, and ranks the evaluated candidate objects based on the calculated matching metric values; and
(iii) a selection component for identifying one or a plurality of candidate objects according to their evaluated ranking, presenting the identified objects to the user, and enabling the user to select one of the presented objects for output to the text display area on the output device.
Preferably, (a) each of the plurality of objects in memory is further associated with one or a plurality of predefined groupings of objects; and (b) the word evaluation component, for each generated input sequence, limits the number of objects for which a matching metric is calculated by identifying one or a plurality of candidate groupings of the objects in memory, and for one or a plurality of objects associated with each of the one or a plurality of identified candidate groupings of objects, calculates a matching metric based on the calculated distance values and the frequency of use associated with each candidate object, and ranks the evaluated candidate objects based on the calculated matching metric values. Further, the keys associated with the characters of the alphabet are arranged in the auto-correcting keyboard region in approximately a standard xe2x80x9cQWERTYxe2x80x9d layout.
Preferably, when a key activation event is detected comprising the simultaneous activation of a plurality of adjacent keys in the auto-correcting keyboard region, a location corresponding to said key activation event is determined as a function of the locations of the simultaneously activated keys, and said determined location is appended to the current input sequence of the locations of the key activation events. Most preferably, the function used to determine the location of said key activation event comprises the computation of the location corresponding to the center of the locations of the simultaneously activated keys. Further, the function used to determine the location of said key activation event comprises the computation of the location corresponding to the weighted center of gravity of the locations of the simultaneously activated keys, wherein the weights associated with each of the keys in the auto-correcting keyboard region correspond to the relative frequencies of occurrence of the characters associated with the keys, wherein said relative frequencies are determined with respect to the frequencies of occurrence of the characters in the objects in memory.
Preferably, when a key activation event is detected comprising the activation of a plurality of adjacent keys in the auto-correcting keyboard region within a predetermined threshold period of time, wherein at all times during said key activation event at least one of said plurality of adjacent keys is activated and wherein at any moment during said key activation event that any subset of said plurality of keys is simultaneously activated, said simultaneously activated subset of keys comprises keys that are contiguously adjacent, a location corresponding to said key activation event is determined as a function of the locations of the entire plurality of adjacent keys detected during said key activation event, and said determined location is appended to the current input sequence of the locations of the key activation events. Most preferably, the function used to determine the location of said key activation event comprises the computation of the location corresponding to the center of the locations of the simultaneously activated keys. Further, the function used to determine the location of said key activation event comprises the computation of the location corresponding to the weighted center of gravity of the locations of the simultaneously activated keys, wherein the weights associated with each of the keys in the auto-correcting keyboard region correspond to the relative frequencies of occurrence of the characters associated with the keys, wherein said relative frequencies are determined with respect to the frequencies of occurrence of the characters in the objects in memory.
Preferably, the auto-correcting keyboard region includes one or a plurality of keys associated with one or a plurality of punctuation characters, wherein said memory includes one or a plurality of objects in memory which include one or a plurality of the punctuation characters associated with keys in said auto-correcting keyboard region. Alternatively, the word evaluation component calculates the matching metric for each candidate object by summing the distance values calculated from determined location in the input sequence to the known location of the key corresponding to the character in the corresponding position of the candidate object, and applying a weighting function according to the frequency of use associated with the object. In another embodiment, at least one of the keys in the auto-correcting keyboard region corresponds to a plurality of characters, one or a plurality of which include various diacritic marks, wherein the plurality of characters comprise variant forms of a single base character, and wherein objects in memory are stored with their correct accented characters.
Preferably, the selection component presents the identified one or a plurality of candidate objects for selection by the user in a candidate object list in the text display area. Most preferably, the selection component identifies the highest ranked candidate object and presents the identified object in the candidate object list in the position nearest to the auto-correcting keyboard region. Further, activation of a key that is associated with a character, wherein the key is not included within the auto-correcting keyboard region, accepts and outputs the determined highest ranked candidate object at a text insertion point in the text display area prior to outputting the selected character at the text insertion point in the text display area. Further, the user selection of an object for output at a text insertion point in the text display area terminates the current input sequence such that the next key activation event within the auto-correcting keyboard region starts a new input sequence.
The present invention further provides a process for auto-correcting text entry system comprising:
(a) providing a user input device comprising a touch sensitive surface including an auto-correcting keyboard region comprising a plurality of the characters of an alphabet, wherein each of the plurality of characters corresponds to a location with known coordinates in the auto-correcting keyboard region, wherein each time a user contacts the user input device within the auto-correcting keyboard region, a location associated with the user contact is determined and the determined contact location is added to a current input sequence of contact locations;
(b) providing a memory containing a plurality of objects, wherein each object is a string of one or a plurality of characters forming a word or a part of a word, wherein each object is further associated with a frequency of use;
(c) providing an output device with a text display area; and
(d) providing a processor coupled to the user input device, memory, and output device, said processor comprising:
(i) a distance value calculation component which, for each determined contact location in the input sequence of contacts, calculates a set of distance values between the contact locations and the known coordinate locations corresponding to one or a plurality of characters within the auto-correcting keyboard region;
(ii) a word evaluation component which, for each generated input sequence, identifies one or a plurality of candidate objects in memory, and for each of the one or a plurality of identified candidate objects, evaluates each identified candidate object by calculating a matching metric based on the calculated distance values and the frequency of use associated with the object, and ranks the evaluated candidate objects based on the calculated matching metric values; and
(iii) a selection component for (a) identifying one or a plurality of candidate objects according to their evaluated ranking, (b) presenting the identified objects to the user, enabling the user to select one of the presented objects for output to the text display area on the output device.
Preferably, the selection component further comprises (c) resetting the current input sequence of the locations of the points of contact to an empty sequence upon detecting the selection by the user of one of the presented objects for output to the text display area on the output device.